Conflicting stories from consultants

On 01 April 2015 I have done an online application to deactivate a 300MB data bundle and activate a 500MB data bundle. The 300MB was deactivated but the 500MB was not activated which resulted in me being charged out of bundle rates so I need this to be rectified and my account to be adjusted accordingly. I have been in contact with the call centre for the last week and at least 3 people (one on 25 May) confirmed that the 500MB was never activated but the lady his morning told me that it was done on 01 April? I dispute this fact as I cannot see this on my last 2 statements. She also transferred me to the accounts department and the lady there transferred me straight back to customer services and the gentleman who received the call dropped my call. I called back again and I spoke to Daniel and he told me to hold on but then I got an engaged tone again. I may mention that I spoke to a lady earlier this week because I received an email that the incident has been closed with no feedback received and she re-opened the incident and asked for my account to be investigated but I received anoyher email yesterday advising me the the incident had been closed? Please assist!